Just wanted to chime in and share my experience with installing osx on my g550 laptop. I have almost the exact same laptop as stated above. This post is a little long-winded and geared towards n00bs like myself
Nvidia 105m - this works flawlessly with the package provided by Moh_vista. I also have an external dell flat panel that osx detects automatically when plugging / unplugging it via hdmi.
I used the myhack installer method. Copied Snow Leopard to a usb stick via a vmware osx image. When installing initially choose ApplePS2Controller or your keyboard and trackpad won't work. After installing update the ApplePS2 kext to VoodooPS2 for better scrolling support for ALPS. If you have an external usb mouse and keyboard you don't have to worry about ApplePS2.
Upgrading to 10.6.2:
Worked fine with no problems.
You can install kexts in 2 different locations. 1) /Library/Extensions 2) /System/Library/Extensions. Make sure to run the pfix utility after installing kexts to make sure they are installed properly!
The audio works fine with VoodooHDA. At first I thought it wasn't working but then I had to go to sound preferences panel. Under the tab output it was defaulting to Digital Out. Change it to speakers. I could not get this to change automatically when plugging earphones in. Maybe another driver works better? Also the internal mic doesn't seem to work. Also the sound was only detected after I ran the pfix utility.
With the supplied Voodoo kexts the battery and power management work fine. The battery icon in the bar correctly shows battery charge etc. However when closing the laptop lid osx hangs and only shows a black screen. Other than that osx has no trouble waking up etc.
Keyboard & Trackpad:
This took me a while to figure out. I finally added an edited trackpad kext to the VoodooPS2Controller kext. Make sure that ApplePS2Controller is not in any of your extensions folders or it will act wonky. With the attached kext two finger scrolling, regular scrolling and tapping work fine. I could not get it to work with any other kexts. IMPORTANT: to get the trackpad to work first install the kext, run pfix then reboot. After that, replace the Trackpad prefPane in /System/Library/PreferencePanes with the supplied Trackpad.prefPane in the zip. After doing this Trackpad should show up in system preferences.
As stated wireless and wired does not work. I picked up this sweet mini adapter
from ebay for only $18 + free shipping. It's wireless n capable and about the size of a penny.
the g550 is a great hackintosh machine and running snow leopard on it is nearly flawless except the internet issues. I've included all the kexts mentioned in my post so you don't have to hunt them down. If you have any questions feel free to ask. If you have a better solution for the sound driver please tell! Thanks.